Multicolor phosphor-converted LED array

ABSTRACT

An array of phosphor pixels is positioned on an array of semiconductor LED pixels with thermally curable adhesive between them. Selected LED pixels of the array are electrically activated; resulting heat cures the adhesive to attach the corresponding phosphor pixel to the activated LED pixel and to release the corresponding phosphor pixel from a carrier. Removal of the carrier removes unattached phosphor pixels, leaving behind phosphor pixels attached to the LED pixels that were activated. The process can be repeated for phosphor pixels of different colors.

BENEFIT CLAIMS TO RELATED APPLICATIONS

This application is a continuation of App No PCT/US2020/055729 filed 15Oct. 2020, which in turn claims priority of U.S. application Ser. No.16/653,414 filed 15 Oct. 2019 (now U.S. Pat. No. 11,063,191) and EP AppNo 20157722.8 filed 17 Feb. 2020. Each one of said applications isincorporated by reference in its entirety.

FIELD OF THE INVENTION

The invention relates generally to phosphor-converted light emittingdiodes (LEDs).

BACKGROUND

Red-Green-Blue (RGB) microLED displays are expected to be the nextgeneration of display technology, due to superior image quality, lowerpower consumption, and increased reliability. Currently, several methodsexist to form large arrays of multi-color, micron-scale, and closelyspaced pixels. One option is to assemble each pixel from individual red,green, and blue LED dice. Another option is to pattern red and greensubpixels onto a blue pixelated die, either via a stamp process,photolithography, or ink-jet printing.

SUMMARY

A method for making a light emitting apparatus comprises positioning aphosphor structure on a semiconductor LED array, and selectivelyoperating selected ones of the multiple semiconductor LED pixels thatconstitute the array. The phosphor structure includes multiple phosphorpixels and is positioned so that each phosphor pixel is aligned with acorresponding semiconductor LED pixel of the array. The phosphorstructure has a layer of thermally curable adhesive thereon; with thephosphor structure positioned on the semiconductor LED array, acorresponding segment of the adhesive is between and in contact witheach phosphor pixel and a light output surface of the correspondingsemiconductor LED pixel. Electrically operating selected ones of thesemiconductor LED pixels causes those pixels to emit light and to heatthe corresponding phosphor pixels to a temperature that at leastpartially cures corresponding discrete segments of the adhesive. Thermalcuring of the adhesive bonds each one of the selected semiconductor LEDpixels to the corresponding phosphor pixel.

The method can further include positioning a second phosphor structureon the semiconductor LED array, and selectively operating selected onesof the multiple semiconductor LED pixels of the second array. Thephosphor pixels of the first phosphor structure are all of a firstcolor; the second phosphor structure includes multiple phosphor pixelsall of a second color different from the first color. The secondphosphor structure is positioned on the semiconductor LED array and thebonded phosphor pixels of the first color, with each phosphor pixel ofthe second color aligned with a corresponding semiconductor LED pixel ofthe array that is not bonded to a phosphor pixel of the first color. Thesecond phosphor structure has a layer of thermally curable adhesivethereon; with the second phosphor structure positioned on thesemiconductor LED array, a corresponding segment of the adhesive isbetween and in contact with each phosphor pixel of the second color andthe corresponding semiconductor LED pixel. Electrically operatingselected ones of the semiconductor LED pixels causes those pixels toemit light and to heat the corresponding phosphor pixels of the secondcolor to a temperature that at least partially cures correspondingdiscrete segments of the adhesive. Thermal curing of the adhesive bondseach of the selected semiconductor LED pixels to the correspondingphosphor pixel of the second color.

A light emitting apparatus includes the semiconductor LED array withmultiple semiconductor LED pixels, multiple corresponding phosphorpixels of multiple different colors, and multiple discrete segments ofthermally cured adhesive. Each phosphor pixel is positioned over a lightemitting surface of a corresponding one of the semiconductor LED pixels.Between each phosphor pixel and the corresponding semiconductor LEDpixel is a corresponding discrete segment of the thermally curedadhesive that attaches the phosphor pixel to the correspondingsemiconductor LED pixel. Each discrete segment of thermally curedadhesive is separated from other discrete segments of thermally curedadhesive between other phosphor pixels and corresponding semiconductorLED pixels of the array.

Objects and advantages pertaining to phosphor-converted light emittingdiodes (LEDs) may become apparent upon referring to the exampleembodiments illustrated in the drawings and disclosed in the followingwritten description or appended claims.

This Summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This Summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended tobe used as an aid in determining the scope of the claimed subjectmatter.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a side cross-sectional schematic diagram of an example of aclose-packed array of multi-colored phosphor-converted LEDS on amonolithic die and substrate. FIG. 1B is a schematic top view of aportion of an example LED display in which each display pixel is a red,green, or blue phosphor-converted LED pixel. FIG. 1C is a schematic topview of a portion of an example LED display in which each display pixelincludes multiple phosphor-converted LED pixels (red, green, and blue)integrated onto a single die that is bonded to a control circuitbackplane.

FIG. 2 is a process flowchart of an example of a disclosed method.

FIGS. 3A, 3B, and 3C are side cross-sectional diagrams thatschematically illustrate position-selective, color-sequenced attachmentof phosphor pixels of three different colors to a semiconductor LEDarray according to an example method.

FIGS. 4A and 4B are side cross-sectional and top views, respectively,that schematically illustrate three parallel attachment processes, ofthe general type illustrated in FIGS. 3A/3B/3C, and use of eachsubstrate carrying phosphor pixels in each of the different parallelprocesses.

FIGS. 5A, 5B, and 5C are analogous to FIGS. 3A, 3B, and 3C but showphosphor pixels of differing colors having differing thicknesses.

The embodiments depicted are shown only schematically; all features maynot be shown in full detail or in proper proportion; for clarity certainfeatures or structures may be exaggerated or diminished relative toothers or omitted entirely; the drawings should not be regarded as beingto scale unless explicitly indicated as being to scale. For example, therelative height, depth, or width of various layers or structures of theLED array, each LED pixels, or phosphor layers or pixels often can beexaggerated relative to others, e.g., the thickness of an underlyingsubstrate. The embodiments shown are only examples and should not beconstrued as limiting the scope of the present disclosure or appendedclaims.

DETAILED DESCRIPTION

The following detailed description should be read with reference to thedrawings, in which identical reference numbers refer to like elementsthroughout the different figures. The drawings, which are notnecessarily to scale, depict selective examples and are not intended tolimit the scope of the disclosure or appended claims. The detaileddescription illustrates by way of example, not by way of limitation, theinventive principles of the present disclosure and appended claims.

The term “GaN LED” is used herein to refer to III-Nitride LEDs, i.e., toLEDs formed in the AlInGaN material system. The examples below aredescribe with reference to such GaN LEDs, but the methods describedherein may be used with III-Phosphide (AlInGaP material system) LEDs orwith LEDs formed in any other suitable material system.

This disclosure describes a monolithic approach to manufacturing a highdensity patterned or multi-color phosphor converted LED array 10,without serial pick and place steps for every single pixel. This avoidsthe significant attach accuracy issues of serial pick and place, whichleads to wide gaps between neighboring pixels. Unlike stamp-basedapproaches, there is no additional patterning step required before theattach process—color selectivity occurs during phosphor integration. Byusing a monolithic approach and a one-step per color attach, accuracycan be enhanced. Additionally, yield improvements can be addressed byincorporating a small number of error correction steps in the phosphorplacement process.

In the methods disclosed herein, a layered carrier assembly includes, inorder, a substrate 30 (e.g., PET), a thermal or UV activated releaseadhesive 32, a layer containing a segmented (pixelated) phosphor array,and a partially cured or highly viscous silicone adhesive 20. Thephosphor pixels 18 on a carrier 30 are typically all of the same color.In many display applications the assembled array will include phosphorpixels 18 of different colors. Phosphor pixels 18 of all colors arereferred to generically or collectively herein as phosphor pixels 18,while phosphor pixels of specific colors are referred to as phosphorpixels 18R (red), 18G (green), and 18B (blue) in an RGB display colorscheme. Other colors, numbers of colors, or combinations of colors canbe used for the phosphor pixels 18.

In formation of a phosphor converted LED array by these methods, thephosphor pixels 18 on the layered carrier assembly are aligned with andplaced in contact with corresponding semiconductor LED pixels 14 in anarray of pixelated semiconductor LED dice, which may for example have aThin-Film Flip Chip (TFFC) architecture. Selected phosphor pixels 18 onthe carrier assembly may then be attached to corresponding semiconductorLED pixels 14, and released from the substrate, by powering (activating)the corresponding semiconductor LED pixels 14 to heat the selectedphosphor pixel 18 to a desired temperature. This releases the thermalrelease adhesive 32 attaching the selected phosphor pixels 18 to thecarrier substrate 30 and cures or partially cures the adhesive 20 on theselected phosphor pixels 18 in contact with the correspondingsemiconductor LED pixels 14. Thus, the step of attaching selectivelybonds pixels 18 of the phosphor layer to corresponding pixels 14 of thearray of pixelated semiconductor LED dice. The layered carrier assemblyand un-bonded phosphor pixels 18 may then be removed, for example with aprocess tape attached (e.g., laminated) to a backside of the substrate30.

If a UV release adhesive 32 is used instead of or in addition to thethermal release adhesive, then UV light emitted by a GaN LED may releasethe corresponding phosphor pixel 18 from the carrier 30.

This process may be repeated with phosphor pixel arrays of differentcolors to produce a multicolor phosphor converted LED array 10. Thefinal device structure may be further heated such that the siliconeadhesive strongly bonds the phosphor pixels 18 to the semiconductor LEDpixels 14.

By using a pre-formed phosphor layer, the color control and yield can behighly controlled by pre-testing and selecting only known-good-phosphorfor integration.

FIG. 1A is a schematic cross-sectional view of a close packed array 10of multi-colored, phosphor converted LEDs on a monolithic die andsubstrate 12, prepared by the methods disclosed herein. The side viewshows GaN LEDs 14 attached to the substrate 12 through metalinterconnects 17 (e.g., gold-gold interconnects or solder attached tocopper micropillars) and metal interconnects 16. Phosphor pixels 18 areattached to corresponding GaN LEDs 14 though an adhesive layer 20, whichmay be a silicone adhesive layer for example. The pixels 18 of thephosphor array can be coated on their sides with a reflective mirror ordiffusive scattering layer 22. In some examples the phosphor pixels 18can be the same height and the same single color; in some examples thephosphor pixels can be of varying heights/thicknesses or differingcolors. In multi-color devices (based on the desired color point)differing phosphor thicknesses facilitates the sequential nature of thephosphor attach process; typically phosphor pixels 18 of the last colorattached will be the thickest (tallest). In some examples an optionalbuffer or clear layer 24 can be disposed on top of the phosphor pixels18. Such a buffer or clear layer 24 can help to maintain the colorpoint, can even out any thickness or height variation among the phosphorpixels 18, or protect the phosphor pixels during subsequent processingsteps (e.g., removing excess material applied as a reflective sidecoating to the phosphor pixels 18).

As summarized above and further explained below with reference to thefigures, self-heating of the semiconductor LED pixels 14 andcorresponding phosphor pixels 18 during operation of the semiconductorLED dice is used to selectively bond pixels 18 from a phosphor array tocorresponding GaN LED pixels 14 to form the phosphor converted LEDarray.

In some examples of display applications, an LED display includes amultitude of display pixels. In some examples (e.g., as in FIG. 1B),each display pixel comprises a single semiconductor LED pixel 14 and acorresponding phosphor pixel 18R, 18G, or 18B of a single color (red,green, or blue). Each display pixel only provides one of the threecolors. In some examples (e.g., as in FIG. 1C), each display pixelincludes multiple semiconductor LED pixels 14 and multiple correspondingphosphor pixels 18 of multiple colors. In the example shown each displaypixel includes a 3×3 array of semiconductor pixels 14; three of thoseLED pixels have red phosphor pixels 18R, three have green phosphorpixels 18G, and three have blue phosphor pixels 18B. Each display pixelcan therefore produce any desired color combination. In the exampleshown the spatial arrangement of the different colored phosphor pixels18 differs among the display pixels; in some examples (not shown) eachdisplay pixel can have the same arrangement of the different coloredphosphor pixels 18.

FIG. 2 is a process flowchart for example methods of the invention.FIGS. 3A, 3B, and 3C illustrate three consecutive sequences of thedevice structure at various stages of each pass of attachment ofphosphor pixels 18.

In step 102, a segmented phosphor array is created on a carrier 30coated with a releasable adhesive 32, e.g. a thermal release layer. Thisarray can be formed by dicing a layer that contains phosphor, or byother methods such as a lithographic or ablation process. The phosphorlayer material may be, for example, phosphor/silicone, ceramic phosphor,phosphor in glass, or phosphor on glass: other suitable phosphormaterials can be employed. Before or after the phosphor layersegmentation step, the surface of the phosphor layer (or of eachphosphor pixel 18) opposite from the surface attached to the carrier 30is coated with a thermally-activated adhesive 20 (e.g., an LED gradesilicone or epoxy adhesive exhibiting low adhesion/G′ at roomtemperature and increased adhesion at higher temperatures).

The carrier 30 may be for example a substrate of PET, sacrificialpolymer, glass, or silicon. The releasable adhesive layer 32 may be athermal or UV activated release adhesive. The thermal or UV releaseadhesive 32 has a shear storage modulus G′>300 KPa at room temperature,which drops below 300 KPa at given elevated temperature to achieveadhesion with the carrier substrate 30. Suitable layered carrierassemblies, e.g. Nitto Revalpha and Adwill D510, include the substrate30 and the thermal activated release adhesive 32. The phosphor layercontains a segmented array of phosphor pixels 18 of a single color, anda partially cured or highly viscous silicone adhesive 20 disposed on asurface of the phosphor pixels 18 opposite from the carrier substrate30.

During mechanical or chemical segmentation, the phosphor layer may bediced into separate M×N arrays such that there are major and minor gapsin the phosphor layer. The major gaps penetrate fully through thecarrier 30 to separate the phosphor layer into the arrays (e.g.,corresponding to a display pixel that includes multiple semiconductorLED pixels 14). The minor gaps cut through phosphor, but stop in thecarrier layer 30, thus creating multiple phosphor pixels 18 in each ofthe separate arrays.

In step 104, the segmented phosphor array is aligned with asemiconductor LED array so that individual phosphor pixels 18 arealigned with corresponding pixels 14 in the array of semiconductor LEDs.In step 106 the phosphor pixels 18 and LED pixels 14 are placed incontact with and optionally weakly bonded to one another. In step 106, aselected subset of the pixels of the LED array is electrically turnedon. During this operation the surface of the selected LED pixels rapidlyheats up, reaching temperatures high enough (e.g., 100° C. to 150° C.)to cause the thermally-activated adhesive 20 between the semiconductorLED pixel 14 and the corresponding phosphor pixel 18 to reflow, creatinga strong bond between each selected LED pixel 14 and the correspondingphosphor pixel 18 at step 108. Simultaneously, down-conversion in thephosphor layer results in additional heating of the phosphor pixel 18,reaching temperatures of, e.g., 150° C. to 200° C. This results in therelease of that phosphor pixel 18 from the thermal release layer 32 onthe carrier 30.

In step 110, the carrier is removed. A corresponding subset of phosphorpixels 18 are bonded to the semiconductor LED pixels 14 that wereoperated during step 106, while the rest remain on the carrier 30 andare removed from the LED array.

The method described is illustrated schematically in FIG. 3A, whichshows a carrier layer 30 with attached blue phosphor pixels 18B alignedover an array of semiconductor LED pixels 14 on the substrate 12. Thecarrier assembly and semiconductor die are brought together so that theadhesive 20 is between and in contact with each phosphor pixel 18B andthe light output surface of each corresponding LED pixel 14. At step 106certain LED pixels 14 are electrically activated (indicated by the whitearrows), which heats the activated LED pixels 14 and correspondingphosphor pixels 18B. At step 108 the elevated temperature results incuring, or at least partial curing, of the adhesive 20, while releasingthe adhesive 32. Note that in the figures solid black layers 20 or 32indicate uncured, released, or non-adhering adhesive, while white layers20 or 32 indicate cured or adhering adhesive. At step 110 the carriersubstrate 30 is removed. Phosphor pixels 18B remain attached tocorresponding LED pixels 14 that were activated at step 106, and areremoved from those LED pixels 14 that were not activated.

Steps 102 through 110 can be repeated to attach phosphor pixels 18 ofother colors. In the example shown, after attachment of blue phosphorpixels 18B to certain LED pixels 14 in FIG. 3A, in FIG. 3B a carriersubstrate with green phosphor pixels 18G is used to attached greenphosphor pixels 18G to certain LED pixels 14 that do not already haveblue phosphor pixels 18B attached. The carrier 30 has a pattern ofphosphor pixels 18G that complements the arrangement of blue phosphorpixels 18B already attached to LED pixels 14. With the green phosphorpixels 18G positioned on the LED pixels 14, certain LED pixels 14 areactivated to cure the adhesive 20 and release the adhesive 32. Removingthe carrier 30 removes the phosphor pixels 18G from LED pixels that werenot activated and leaves phosphor pixels 18G attached to those LEDpixels 14 that were activated. The process can be repeated again as inFIG. 3C to attach red phosphor pixels 18R to those pixels not alreadyattached to blue or green phosphor pixels 18B or 18G. The order ofcolors is only an example; any order can be employed, and differentorderings can be advantageously employed for producing the complementaryarrangements of phosphor pixels 18 on the carrier 30 that are needed forphosphor pixels 18 of second and subsequent colors to be attached.

FIGS. 4A and 4B illustrate schematically three parallel phosphor pixelattachment sequences that are each similar to the sequence illustratedin FIGS. 3A through 3C. Phosphor pixels of a first color are attached tocertain LED pixels 14 as described above and shown in FIG. 3A (redpixels 18R in the left sequence, green pixels 18G in the centersequence, and blue pixels 18B in the right sequence). After removing thecarriers 30 and their remaining phosphor pixels 18, each carrier 30 isshifted to a different sequence (indicated by the diagonal arrows inFIG. 4A), where its pattern of missing phosphor pixels 18 (those leftbehind attached to LED pixels 14) is the complementary pattern neededfor attachment of a second color to an LED array already having thatsame arrangement of attached phosphor pixels 18. After attachment ofphosphor pixels 18 of a second color to certain LED pixels 14 asdescribed above and shown in FIG. 3B, the carriers 30 are shifted againfor attaching phosphor pixels of a third color, as shown in FIG. 3C.

The top view shown in FIG. 4B illustrates an example of a sequence ofphosphor pixel arrangements that result from the sequences of FIG. 4A,and resemble the example shown in FIG. 1B. Beginning with a bare 3×3array of semiconductor LED pixels 14, phosphor pixels of a first colorare attached as described above in a first pattern (diagonal in thisexample); the first pattern is the same for three different first colorson three different LED arrays. After that first color attachmentsequence, each array of phosphor pixels 18 is left with gapscorresponding to those pixels left behind, and can now fit onto one ofthe other LED arrays that has a first color attached. Phosphor pixels 18of a second color are attached as described above in a second pattern;the second pattern is the same for three different second colors on thethree different LED arrays. With removal of a second set of phosphorpixels 18, each carrier can now fit over attached phosphor pixels 18 ofthe two previously attached colors. At the end, in some examples theentire LED array can be covered with phosphor pixels 18 (as shown). Inother examples (not shown), some LED pixels 14 can be left without acorresponding phosphor pixel 18; such an arrangement can be suitable,e.g., when the direct output of the LED pixel 14 is one of the desiredcolors for the display. Although 3×3 LED arrays are shown in theexamples, the disclosed methods can be employed to produce multi-colorphosphor converted LED arrays of any size or number of pixels.

In one specific example, a silicone/phosphor film is fully cured andthen laminated onto a PET substrate 30 coated with a thermal releaseadhesive 32. A thin layer of silicone adhesive 20 is deposited onto thephosphor film surface, e.g., via spin-coating, after which excesssolvent is removed with a short bake step. The phosphor film/PET stackis then diced into 3×3 arrays, where every third saw line cuts fullythrough the PET to singulate the arrays (other saw lines cut throughphosphor, but stop in PET layer). The arrays are then aligned andattached onto a pixelated TFFC die using a pick-and-place tool. Noelevated temperature or force is used during the attach process, leadingto a weak bond between the die and the silicone adhesive on the phosphorpixels 18. Electrical contact is then made to power a selected patternof die LED pixels 14, which are run at a set current for a certainlength of time (in the case of devices shown in FIG. 4 , 4A/mm² for 15seconds). A tape is laminated to the top of the PET carrier 30 and thenused to remove the PET carrier 30 and un-bonded phosphor pixels 18.

As noted above, in some examples the release adhesive 32 can beUV-releasable. A UV-releasable adhesive 32 can be employed in exampleswherein the light output of the semiconductor LED pixels 14 is of awavelength suitable for releasing the adhesive, e.g., a UV GaN LED.

The phosphor pixel attachment sequences shown in FIGS. 5A through 5C areanalogous to those of FIGS. 3A through 3C, except that phosphor pixels18 of different colors have different thicknesses. Such thicknessdifference might arise in some examples due to different opticalcharacteristics of different phosphors (e.g., absorption coefficient orconversion efficiency). In some examples, differing thicknesses canfacilitate the phosphor attachment sequences disclosed herein. If thedifferent colored phosphor pixels 18 are attached in order of thinnestto thickest (as in FIGS. 5A-5C), then at each subsequent attachmentstage there is a gap between the carrier substrate 30 and phosphorpixels 18 already attached to the corresponding LED pixels 14. That canbe advantageous, e.g., to ensure that subsequently attached phosphorpixels 18 can make contact with the corresponding LED pixels (i.e.,without interference from a too-thick phosphor pixel 18 already attachedto an LED pixel 14), or to avoid potentially undesirable contact betweenan attached phosphor pixel 18 and the carrier 30 or release adhesiveresidue thereon.

Although the thermally-released carrier 30 is removed at the end of theattach process, the disclosed inventive methods result in a discretesegment of the thermally activated adhesive layer 20 between eachattached phosphor pixel 18 and the light output surface of thecorresponding semiconductor LED pixel 14. Each adhesive layer segment 20is separated from other such segments between other pairs of phosphorand LED pixels 18 and 14. The presence of such discrete adhesive layersegments 20 and the fully aligned segmentation of both the adhesivelayer 20 and the phosphor pixels 18 (i.e., aligned with the underlyingLED pixels 14) can indicate the use of the disclosed inventive methods.Other indicators of those methods may include the different thicknesses(i.e., heights) of the phosphor pixels depending on the number ofattachment steps used to attach phosphor pixels of different colors.Finally, the metal traces/tie bars used to electrically activate theappropriate pixels during the attach process also can be indicative ofthe use of the disclosed inventive methods.

This disclosure is illustrative and not limiting. Further modificationswill be apparent to one skilled in the art in light of this disclosureand are intended to fall within the scope of the appended claims. One ofskill can extend the disclosed inventive apparatus and methods tovertical thin film (VTF) and similar LED architectures.

In addition to the preceding, the following example embodiments fallwithin the scope of the present disclosure or appended claims:

Example 1. A light emitting apparatus comprising: (a) a semiconductorLED array comprising multiple semiconductor LED pixels; (b) multiplecorresponding phosphor pixels of multiple different colors, with eachphosphor pixel being positioned over a light emitting surface of acorresponding one of the semiconductor LED pixels; and (c) between eachphosphor pixel and the corresponding semiconductor LED pixel, acorresponding discrete segment of thermally cured adhesive that attachesthe phosphor pixel to the corresponding semiconductor LED pixel, eachdiscrete segment of thermally cured adhesive being separated from otherdiscrete segments of thermally cured adhesive between other phosphorpixels and corresponding semiconductor LED pixels of the array.

Example 2. The light emitting apparatus of Example 1, further comprisingone or more metal traces or tie bars arranged and connected so as toenable selective electrical operation of selected ones of thesemiconductor LED pixels.

Example 3. The light emitting apparatus of any one of Examples 1 or 2,wherein the phosphor pixels exhibit differing thicknesses.

Example 4. The light emitting apparatus of any one of Examples 1 through3, wherein the thermally cured adhesive exhibits a cure temperaturebetween about 100° C. and about 150° C.

Example 5. The light emitting apparatus of any one of Examples 1 through4, wherein the thermally cured adhesive is a silicone.

Example 6. The light emitting apparatus of any one of Examples 1 through5, wherein the thermally cured adhesive has a refractive index betweenabout 1.4 and about 1.6.

Example 7. The light emitting apparatus of any one of Examples 1 through6, wherein the phosphor pixels include one or more of phosphor/silicone,ceramic phosphor, phosphor in glass, or phosphor on glass.

Example 8. A method for making the light emitting apparatus of any oneof Examples 1 through 7, the method comprising: (A) positioning thephosphor structure on the semiconductor LED array, with each phosphorpixel aligned with a corresponding semiconductor LED pixel of the array,and with a corresponding segment of the adhesive between and in contactwith each phosphor pixel and the light output surface of thecorresponding semiconductor LED pixel; and (B) electrically operatingselected ones of the semiconductor LED pixels to emit light and to heatthe corresponding phosphor pixels to a temperature that at leastpartially cures corresponding discrete segments of the adhesive andbonds each one of the selected semiconductor LED pixels to thecorresponding phosphor pixel.

Example 9. A method for making a light emitting apparatus, the methodcomprising: (A) positioning on a semiconductor LED array comprisingmultiple semiconductor LED pixels a phosphor structure comprisingmultiple phosphor pixels with each phosphor pixel aligned with acorresponding semiconductor LED pixel of the array, the phosphorstructure having a layer of thermally curable adhesive thereon so that,with the phosphor structure positioned on the semiconductor LED array, acorresponding segment of the adhesive is between and in contact witheach phosphor pixel and a light output surface of the correspondingsemiconductor LED pixel; and (B) electrically operating selected ones ofthe semiconductor LED pixels to emit light and to heat the correspondingphosphor pixels to a temperature that at least partially curescorresponding discrete segments of the adhesive and bonds each one ofthe selected semiconductor LED pixels to the corresponding phosphorpixel.

Example 10. The method of Example 9, wherein the thermally curedadhesive exhibits a cure temperature between about 100° C. and about150° C.

Example 11. The method of any one of Examples 9 or 10, wherein thethermally cured adhesive is a silicone.

Example 12. The method of any one of Examples 9 through 11, wherein thethermally cured adhesive has a refractive index between about 1.4 andabout 1.6.

Example 13. The light emitting apparatus of any one of Examples 9through 12, wherein the phosphor layer includes one or more ofphosphor/silicone, ceramic phosphor, phosphor in glass, or phosphor onglass.

Example 14. The method of any one of Examples 9 through 13, wherein (i)the phosphor structure includes a substrate, (ii) surfaces of thephosphor pixels opposite from the semiconductor LED array are attachedto the substrate by a thermally releasable adhesive, and (iii) operatingthe selected ones of the semiconductor LED pixels to emit light and toheat the corresponding phosphor pixels releases the correspondingphosphor pixels from the substrate.

Example 15. The method of Example 14, wherein the thermally releasableadhesive exhibits a release temperature between about 150° C. and about220° C.

Example 16. The method of any one of Examples 14 or 15, furthercomprising removing from the semiconductor LED array the substrate andthose phosphor pixels not released from the substrate.

Example 17. The method of any one of Examples 9 through 13, wherein (i)the phosphor structure includes a substrate, (ii) surfaces of thephosphor pixels opposite from the semiconductor LED array are attachedto the substrate by a UV releasable adhesive, and (iii) operating theselected ones of the semiconductor LED pixels to emit UV light releasesthe corresponding phosphor pixels from the substrate.

Example 18. The method of Example 17, further comprising removing fromthe semiconductor LED array the substrate and those phosphor pixels notreleased from the substrate.

Example 19. The method of any one of Examples 9 through 18, wherein thephosphor pixels of the phosphor structure are all of a first color, themethod further comprising: (C) positioning on the semiconductor LEDarray and the bonded phosphor pixels of the first color a secondphosphor structure comprising multiple phosphor pixels all of a secondcolor different from the first color, with each phosphor pixel of thesecond color aligned with a corresponding semiconductor LED pixel of thearray that is not bonded to a phosphor pixel of the first color, thesecond phosphor structure having a layer of thermally curable adhesivethereon so that, with the second phosphor structure position on thesemiconductor LED array, a corresponding segment of the adhesive isbetween and in contact with each phosphor pixel of the second color andthe corresponding semiconductor LED pixel; and (D) electricallyoperating selected ones of the semiconductor LED pixels to emit lightand to heat the corresponding phosphor pixels of the second color to atemperature that at least partially cures corresponding discretesegments of the adhesive and bonds each of the selected semiconductorLED pixels to the corresponding phosphor pixel of the second color.

Example 20. The method of Example 19, wherein (i) the second phosphorstructure includes a second substrate, (ii) surfaces of the phosphorpixels of the second color opposite from the semiconductor LED array areattached to the second substrate by a thermally releasable adhesive, and(iii) operating the selected ones of the semiconductor LED pixels toemit light and to heat the corresponding phosphor pixels of the secondcolor releases the corresponding phosphor pixels of the second colorfrom the second substrate.

Example 21. The method of Example 20, further comprising removing fromthe semiconductor LED array the second substrate and those phosphorpixels of the second color not released from the second substrate.

Example 22. The method of Example 19, wherein (i) the second phosphorstructure includes a second substrate, (ii) surfaces of the phosphorpixels of the second color opposite from the semiconductor LED array areattached to the second substrate by a UV releasable adhesive, and (iii)operating the selected ones of the semiconductor LED pixels to emit UVlight releases the corresponding phosphor pixels of the second colorfrom the second substrate.

Example 23. The method of Example 22, further comprising removing fromthe semiconductor LED array the second substrate and those phosphorpixels of the second color not released from the second substrate.

Example 24. The method of any one of Examples 19 through 23, wherein thephosphor pixels of the second color are thicker than the phosphor pixelsof the first color.

It is intended that equivalents of the disclosed example embodiments andmethods shall fall within the scope of the present disclosure orappended claims. It is intended that the disclosed example embodimentsand methods, and equivalents thereof, may be modified while remainingwithin the scope of the present disclosure or appended claims.

In the foregoing Detailed Description, various features may be groupedtogether in several example embodiments for the purpose of streamliningthe disclosure. This method of disclosure is not to be interpreted asreflecting an intention that any claimed embodiment requires morefeatures than are expressly recited in the corresponding claim. Rather,as the appended claims reflect, inventive subject matter may lie in lessthan all features of a single disclosed example embodiment. Therefore,the present disclosure shall be construed as implicitly disclosing anyembodiment having any suitable subset of one or more features—whichfeatures are shown, described, or claimed in the presentapplication—including those subsets that may not be explicitly disclosedherein. A “suitable” subset of features includes only features that areneither incompatible nor mutually exclusive with respect to any otherfeature of that subset. Accordingly, the appended claims are herebyincorporated in their entirety into the Detailed Description, with eachclaim standing on its own as a separate disclosed embodiment. Inaddition, each of the appended dependent claims shall be interpreted,only for purposes of disclosure by said incorporation of the claims intothe Detailed Description, as if written in multiple dependent form anddependent upon all preceding claims with which it is not inconsistent.It should be further noted that the cumulative scope of the appendedclaims can, but does not necessarily, encompass the whole of the subjectmatter disclosed in the present application.

The following interpretations shall apply for purposes of the presentdisclosure and appended claims. The words “comprising,” “including,”“having,” and variants thereof, wherever they appear, shall be construedas open ended terminology, with the same meaning as if a phrase such as“at least” were appended after each instance thereof, unless explicitlystated otherwise. The article “a” shall be interpreted as “one or more”unless “only one,” “a single,” or other similar limitation is statedexplicitly or is implicit in the particular context; similarly, thearticle “the” shall be interpreted as “one or more of the” unless “onlyone of the,” “a single one of the,” or other similar limitation isstated explicitly or is implicit in the particular context. Theconjunction “or” is to be construed inclusively unless: (i) it isexplicitly stated otherwise, e.g., by use of “either . . . or,” “onlyone of,” or similar language; or (ii) two or more of the listedalternatives are understood or disclosed (implicitly or explicitly) tobe incompatible or mutually exclusive within the particular context. Inthat latter case, “or” would be understood to encompass only thosecombinations involving non-mutually-exclusive alternatives. In oneexample, each of “a dog or a cat,” “one or more of a dog or a cat,” and“one or more dogs or cats” would be interpreted as one or more dogswithout any cats, or one or more cats without any dogs, or one or moreof each. In another example, each of “a dog, a cat, or a mouse,” “one ormore of a dog, a cat, or a mouse,” and “one or more dogs, cats, or mice”would be interpreted as (i) one or more dogs without any cats or mice,(ii) one or more cats without and dogs or mice, (iii) one or more micewithout any dogs or cats, (iv) one or more dogs and one or more catswithout any mice, (v) one or more dogs and one or more mice without anycats, (vi) one or more cats and one or more mice without any dogs, or(vii) one or more dogs, one or more cats, and one or more mice. Inanother example, each of “two or more of a dog, a cat, or a mouse” or“two or more dogs, cats, or mice” would be interpreted as (i) one ormore dogs and one or more cats without any mice, (ii) one or more dogsand one or more mice without any cats, (iii) one or more cats and one ormore mice without and dogs, or (iv) one or more dogs, one or more cats,and one or more mice; “three or more,” “four or more,” and so on wouldbe analogously interpreted.

For purposes of the present disclosure or appended claims, when termsare employed such as “about equal to,” “substantially equal to,”“greater than about,” “less than about,” and so forth, in relation to anumerical quantity, standard conventions pertaining to measurementprecision and significant digits shall apply, unless a differinginterpretation is explicitly set forth. For null quantities described byphrases such as “substantially prevented,” “substantially absent,”“substantially eliminated,” “about equal to zero,” “negligible,” and soforth, each such phrase shall denote the case wherein the quantity inquestion has been reduced or diminished to such an extent that, forpractical purposes in the context of the intended operation or use ofthe disclosed or claimed apparatus or method, the overall behavior orperformance of the apparatus or method does not differ from that whichwould have occurred had the null quantity in fact been completelyremoved, exactly equal to zero, or otherwise exactly nulled.

For purposes of the present disclosure and appended claims, anylabelling of elements, steps, limitations, or other portions of anembodiment, example, or claim (e.g., first, second, third, etc., (a),(b), (c), etc., or (i), (ii), (iii), etc.) is only for purposes ofclarity, and shall not be construed as implying any sort of ordering orprecedence of the portions so labelled. If any such ordering orprecedence is intended, it will be explicitly recited in the embodiment,example, or claim or, in some instances, it will be implicit or inherentbased on the specific content of the embodiment, example, or claim. Inthe appended claims, if the provisions of 35 USC § 112(f) are desired tobe invoked in an apparatus claim, then the word “means” will appear inthat apparatus claim. If those provisions are desired to be invoked in amethod claim, the words “a step for” will appear in that method claim.Conversely, if the words “means” or “a step for” do not appear in aclaim, then the provisions of 35 USC § 112(f) are not intended to beinvoked for that claim.

If any one or more disclosures are incorporated herein by reference andsuch incorporated disclosures conflict in part or whole with, or differin scope from, the present disclosure, then to the extent of conflict,broader disclosure, or broader definition of terms, the presentdisclosure controls. If such incorporated disclosures conflict in partor whole with one another, then to the extent of conflict, thelater-dated disclosure controls.

The Abstract is provided as required as an aid to those searching forspecific subject matter within the patent literature. However, theAbstract is not intended to imply that any elements, features, orlimitations recited therein are necessarily encompassed by anyparticular claim. The scope of subject matter encompassed by each claimshall be determined by the recitation of only that claim.

What is claimed is:
 1. An apparatus comprising: a semiconductor LEDarray comprising multiple semiconductor LED pixels; a first set ofmultiple phosphor pixels, (i) each phosphor pixel of the first set beingpositioned over a light emitting surface of a corresponding LED pixel ofa first subset of the LED pixels and attached to that corresponding LEDpixel by a thermally curable adhesive in a cured state, (ii) a secondsubset of the LED pixels having no corresponding phosphor pixel of thefirst set attached thereto; and a second set of multiple phosphor pixelsarranged on a carrier substrate, each phosphor pixel of the second sethaving a corresponding layer of the thermally curable adhesive, in anuncured state, on a surface of the phosphor pixel opposite the carriersubstrate, the phosphor pixels of the first and second sets beingarranged on the LED array and the carrier substrate, respectively, sothat with the LED array and the carrier substrate suitably alignedsubstantially parallel to each other with the light emitting surfaces ofthe LED pixels facing the phosphor pixels of the second set, (i) eachphosphor pixel of the first set is aligned with a corresponding area ofthe carrier substrate that lacks a phosphor pixel of the second set, and(ii) each phosphor pixel of the second set is aligned with acorresponding one of the LED pixels that lacks a phosphor pixel of thefirst set.
 2. The apparatus of claim 1, further comprising one or moremetal traces or tie bars arranged and connected so as to enableselective electrical operation of selected ones of the semiconductor LEDpixels.
 3. The apparatus of claim 1, the phosphor pixels of the firstset having corresponding thicknesses less than thickness of any phosphorpixel of the second set.
 4. The apparatus of claim 1, the thermallycurable adhesive having a cure temperature between about 100° C. andabout 150° C.
 5. The apparatus of claim 1, the thermally curableadhesive including a silicone.
 6. The apparatus of claim 1, thethermally curable adhesive having a refractive index between about 1.4and about 1.6.
 7. The apparatus of claim 1, the phosphor pixels of thefirst or second sets including one or more of phosphor/silicone, ceramicphosphor, phosphor in glass, or phosphor on glass.
 8. The apparatus ofclaim 1, the phosphor pixels of the first and second sets being all asingle color.
 9. The apparatus of claim 1, the LED array and the carriersubstrate being aligned substantially parallel to each other with thelight emitting surfaces of the LED pixels facing the phosphor pixels ofthe second set, so that (i) each phosphor pixel of the first set isaligned with a corresponding area of the carrier substrate that lacks aphosphor pixel of the second set, and (ii) each phosphor pixel of thesecond set is aligned with a corresponding one of the LED pixels thatlacks a phosphor pixel of the first set.
 10. The apparatus of claim 9,the adhesive on the phosphor pixels of the second set being in contactwith the light emitting surfaces of the corresponding LED pixels. 11.The apparatus of claim 1, the phosphor pixels of the second set beingattached to the carrier substrate by a UV releasable adhesive in anadhered state, the LED pixels being UV emitters.
 12. The apparatus ofclaim 11, areas of the carrier substrate, that lack a phosphor pixel ofthe second set, having thereon a layer of the UV releasable adhesive ina released state.
 13. The apparatus of claim 1, the phosphor pixels ofthe second set being attached to the carrier substrate by a thermallyreleasable adhesive in an adhered state.
 14. The apparatus of claim 13,the thermally releasable adhesive having a release temperature betweenabout 150° C. and about 220° C.
 15. The apparatus of claim 13, areas ofthe carrier substrate, that lack a phosphor pixel of the second set,having thereon a layer of the thermally releasable adhesive in areleased state.
 16. The apparatus of claim 1, the phosphor pixels of thefirst set including phosphor pixels of one or more colors, the phosphorpixels of the second set including phosphor pixels of at least one colordifferent from the color of any phosphor pixel of the first set.
 17. Theapparatus of claim 16, the phosphor pixels of the second set being all asingle color.
 18. The apparatus of claim 17, the phosphor pixels of thefirst set being all a single color.
 19. The apparatus of claim 17, thephosphor pixels of the first set including at least two differentcolors.
 20. The apparatus of claim 17, the phosphor pixels of the firstset including at least three different colors.